Stimulation of recovery from underground deposits

ABSTRACT

Chemically stable liquid reactants capable of forming an explosive reaction mixture are injected into a fluid or mineral bearing formation, which may first be hydraulically fractured. An inert spacing medium is injected intermediate to the injection of the reactants so that the explosive mixture is formed at some desired radial distance from the wellbore. The reactants may be such that the explosive mixture autodetonates with the passage of time or may be detonated by shock, as by the detonation of a conventional detonating device. The reactants may also be injected in cycles, each cycle comprising the reactants separated by a slug of inert spacing medium. The amount of spacer may be varied during the treating operation, as by decreasing the amount of spacing medium during the operation, so that the explosive reaction mixtures are formed in concentric regions of the formation surrounding the wellbore. The first reactant may be used as a hydraulic fracturing fluid, and contain conventional and/or shock-sensitive explosive propping agents. Upon detonation of the explosive reaction mixtures, the formation is fractured in a radial manner with the resulting fractures propagated both outward into the formation and inward toward the wellbore so as to enhance the subsequent recovery of minerals or fluids from the formation.

United States Patent [72! Inventor Ray M. Kelseaux Tulsa, Okla. [21 I Appl. No. 796,230 [22] Filed Feb. 3, 1969 [45] Patented July 20, 1971 [73] Assignec CitiesServiceOil Company Tulsa, Okla.

[54] STIMULATION OF RECOVERY FROM UNDERGROUND DEPOSITS 20 Claims, 1 Drawing Fig.

[52] U.S. C1 166/280, 102/23, 166/299, 166/300 [51] Int. Cl E2lb 43/26 [50] Field of Search 166/280, 299, 300; 102/21, 23; 149/22; 299/13 56] References Cited UNITED STATES PATENTS 2,708,876 5/1955 Nowak 166/299 3,075,463 1! 1963 Eilers et al. 166/299 3,270,815 9/1966 Osborn etal. 166/299 3,314,477 4/1967 Boevers et al....... 166/299 X 3,336,982 8/1967 Woodward et al.1 166/299 3,342,262 9/1967 King et a1 166/300 UX 3,378,416 4/1968 Perry et al. 149/22 Primary Examiner-Jan A. Calvert Attorney-J. Richard Geaman ABSTRACT: Chemically stable liquid reactants capable of forming an explosive reaction mixture are injected into a fluid or mineral bearing formation, which may first be hydraulically fractured. An inert spacing medium is injected intermediate to the injection of the reactants so that the explosive mixture is formed at some desired radial distance from the wellbore. The reactants may be such that the explosive mixture autodetonates with the passage of time or may be detonated by shock, as by the detonation of a conventional detonating device. The reactants may also be injected in cycles, each cycle comprising the reactants separated by a slug of inert spacing medium. The amount of spacer may be varied during the treating operation, as by decreasing the amount of spacing medium during the operation, so that the explosive reaction mixtures are formed in concentric regions of the formation surrounding the wellbore. The first reactant may be used as a hydraulic fracturing fluid, and contain conventional and/or shock-sensitive explosive propping agents. Upon detonation of the explosive reaction mixtures, the formation is fractured in a radial manner with the resulting fractures propagated both outward into the formation and inward toward the wellbore so as to enhance the subsequent recovery of minerals or fluids from the formation.

PATENTED JUL20|97I 3593,- 793 RAY M. KELSEAUX INVENTOR.

STIMULATION OF RECOVERY FROM UNDERGROUND DEPOSITS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the treatment of underground deposit-bearing formations. More particularly, it relates to an improved method for fracturing such underground formations to enhance or stimulate the recovery of the desired deposits therefrom.

2. Description of the Prior Art It is well known in the art that the recovery of minerals and fluids from underground formations of relatively low permeability can be enhanced by fracturing the formation rock to create areas of a high permeability. One commonly employed technique for fracturing such formations is hydrofracturing. In this technique, a fracturing fluid is injected into the formation through a wellbore at a pressure above the formation break down pressure. The fracture initiates at the wellbore and hopefully propagates outward into the formation in a radial manner. While this technique is generally useful, complete radial coverage of the formation and controlled propagation of the fracture at increasing distances from the wellbore are generally not achieved.

The use of explosives implanted in crevices, cracks, or fissures is common in mining and quarrying operations. Such explosives have included both solid and liquid-type explosives. The detonation of an explosive device or materials in a wellbore to achieve explosive fracturing of the surrounding formation, however, suffers from the same disadvantage noted above with respect to hydrofracturing operations, namely the difficulty of propagating the fracture at increasing distances from the injection wellbore. Explosive fracturing by the detonation of an explosive device in a wellbore also requires a subsequent cleanup operation before recovery operations can be begun at that wellsite, increasing both the time and expense involved in such a treating action.

It is an object of the present invention, therefore, to provide an improved method for stimulating the recovery of materials from underground deposits.

It is another object of the invention to provide an improved process for fracturing underground formations.

It is another object of the invention to provide for enhancing the radial propagation of the fracture into the formation around a wellbore.

It is a further object of the invention to provide a process for extending the distance from the wellbore to which the fracture may be propagated.

It is a further object of the invention to provide a process for the explosive fracturing of a formation in which the necessity for subsequently cleaning up the injection wellbore may be obviated.

With these and other objects in mind, the invention is hereafter set forth in detail, the novel features thereof being pointed out in the appended claims.

SUMMARY OF THE INVENTION The objects of the present invention are accomplished by a process in which an explosive reaction mixture is formed in situ at a generally predetermined radial distance from the wellbore used to inject the components of the mixture into the formation. The components of the mixture are chemically stable, liquid reactants, which, when mixed, are capable of forming an explosive reaction mixture. The reactants are injected into the formation separately and are separated by an inert spacing medium that is injected intermediate to the injection of the reactants. The reactants may be injected in cycles, with each cycle comprising a portion of the liquid reactants separated by an inert spacing medium. The radial distance from the injection wellbore at which the reactants mix to form an explosive reaction mixture can be varied by decreasing the amount of spacing medium employed during the treating operation. In this manner, the explosive reaction mixtures may be formed in generally concentric rings at increasing distances from the injection wellbore. Upon detonation, a cascading explosive effect can thereby be accomplished propagating from ring-to-ring. In this manner, the effective fracture area may be enhanced.

The liquid reactants employed may be such that the resulting explosive reactive mixtures are either shock sensitive or are autodetonating with the passage of time. Where a shock sensitive mixture is formed, it is necessary to provide some means for detonating the explosive reaction mixture, suchas by actuation of an auxiliary detonation device positioned in the wellbore.

If desired, the reactants may be placed and the explosive reaction mixture detonated after conventional hydraulic fracturing has been performed. Alternately, the first liquid reactant may be employed as a hydraulic fracturing fluid by injection at a pressure at least equal to the formation breakdown pressure. Conventional propping agents may be employed in conjunction with an initial hydraulic fracturing fluid and/or with the first liquid reactant when this material is also employed as a hydraulic fracturing fluid. Shock sensitive explosive pellets may also be injected in conjunction with the first liquid reactant, so that the detonation of the explosive reaction mixtures will cause further detonations enhancing the propagation of the fracture into the formation.

BRIEF DESCRIPTION OF THE DRAWING The present invention is hereinafter described in further detail with particular reference to the accompanying drawing in which:

The FIGURE shows a cross-sectional view of a well in a sub terranean formation illustrating the disposition of several cyclic rings of a first chemically stable liquid reactant, an inert spacing medium and a second chemically stable liquid reactant, etc.

DETAILED DESCRIPTION OF THE INVENTION The present invention permits the safe and effective placement of chemically stable liquid reactants at a generally predetermined radial distance from a wellbore in a depositbearing fonnation. As disclosed above, the reactants are such that, upon mixing, they form an explosive reaction mixture. This explosive mixture may be either autodetonating with the passage of time or shock sensitive. As indicated in Perry et al., US. Pat. No. 3,378,4I6, liquid explosive compositions are commercially available that are relatively hypersensitive to shock and may be detonated by some form of actuating device. Any such commercially available explosive compositions that can be prepared by mixing individual components thereof can be prepared and placed in accordance with the practice of the present invention.

The invention, however, is particularly suited to the utilization of liquid compositions that are autodetonating with the passage of time. Such compositions can be safely and effectively placed and mixed in the formation without the need for any auxiliary detonation means and without the necessity for any cleanup operations in the wellbore prior to the commencement of recovery operations. The Perry patent discloses that polynitro organics and organic boron compounds can be mixed to form explosive reaction mixtures. It is within the scope of this invention to inject these compounds into the formation to form the desired autodetonating mixtures in situ.

Perry indicates that the polynitro compounds can be highly purified polynitro compounds or the nitration mixtures of substance where two or more hydrogens are replaced by NO, groups. Examples of suitable polynitro aliphatic compounds are the polynitroparaffins such as the di-, triand tetranitroparaffins as well as the di-, tri-, and tetranitrated esters of aliphatic alcohols, aliphatic glycols and aliphatic polyglycols. Illustrative examples of such compounds include tetranitromethane and tetranitroglycerine.

The coreactant employed with such a polynitro compound can be any suitable carborane liquid including substituted carboranes, such as alkylcarboranes or hydroxyalkylcarboranes.

It will be appreciated by those skilled in the art, however, that the particular reactants employed in the practice of this invention are not a critical feature of the invention. Various factors will be involved in the choice of the particular reactants for any given application of this invention, including the explosive potency the reactant contributes to the explosive reaction mixture, their commercial availability, relative cost and relative insensitivity toward detonation prior to mixing with the desired coreactant.

When the resulting explosive reaction mixture formed in situ in the formation is of an autodetonating type, no auxiliary detonation means, of course, are required. When the resulting mixtures are shock sensitive but not self detonating an auxiliary detonation device of some kind is required. Such devices are known in the art and need not be described in detail herein other than to note that such devices would include those that are electrically actuated or that may be detonated by some standard form of self timing mechanism to actuate the device. it is within the scope of the term detonation device," as employed herein, to provide a charge of conventional explosives such as dynamite or nitroglycerine, positioned in the wellbore or the adjacent formation as the auxiliary device to cause the detonation of the explosive reaction mixtures formed in situ in the formation. it is also within the scope of this invention to provide more than one explosive reaction mixture and to inelude both autodetonating and shock sensitive reaction mixtures in one treating operation.

The inert spacing medium employed should be one that is relatively inert with respect to each of the reactants in conjunction with which it is employed. Water, oil or other liquids may be employed depending upon the circumstances.

The total amount of reactants employed will depend upon a variety of factors including the permeability characteristics of the formation, the explosive capability of the explosive mixture, the type of operations to be carried out thereafter, and the like. The amount of spacing medium employed will vary depending upon the distance from the wellbore at which it is desired that the reactants meet and mix. As the reactants and the spacing medium move outward from the wellbore in increasing circular bands, the reactants gradually approach each other as the band of spacing medium narrows. Upon mixing and detonation in a generally circular region of the formation around the wellbore, explosive fracturing of the formation results, with the resulting fractures propagated both outward into the formation and inward toward the wellbore, so as to enhance the effective area in which the explosive action is effective.

The point at which the reactants are placed and the detonation occurs, therefore, is controlled to a significant extent by the amount of spacing medium employed. in one embodiment of th invention, the reactants are introduced into the formation in cycles. Each cycle comprises a portion of the total amount of reactants to be employed, separated by an inert spacing medium. By varying the relative amount of spacer, as by decreasing the relative amount of spacer during the treating operation, the explosive reaction mixtures can be formed in concentric rings at increasing distances from the injection wellbore. Upon detonation in this instance, a cascading explosive effect can be accomplished with the fracturing force being propagated from ring-to-ring.

Referring to the FIGURE the particular disposition of the cyclic rings of chemically stable liquid reactants and the inert spacing media are shown. Well it) is drilled into formation ll through which radially extending fractures have been propagated. A first chemically stable liquid reactant H9 is injected into the well, followed by inert spacing medium 18. Subsequently, a second chemically stable liquid reactant 117 is introduced with an additional inert spacing medium to. This sequential operation is followed by another injection ofa first chemically stable liquid reactant 15, followed by inert spacing medium 14 and a second chemically stable liquid reactant 13,

followed by inert spacing medium 12. The inert spacing medium 12 is injected in sufficient quantity so as to drive the chemically stable liquid reactants 13 and 15 together in a predetermined distance from the well and chemically stable liquid reactant l7 and R9 together at another predetermined spacing a distance into the formation. Therefore, by the sequential injection of chemically stable liquid reactants, followed by inert spacing media, the explosive mixtures of the liquid reactants may be placed any desired distance from the well. The explosive mixtures are then detonated so as to completely fracture the formation for subsequent recovery of minerals therefrom. The last addition of inert spacing medium 12 is added to the formation in sufficient quantity such that the two chemically stable liquid reactants l3 and 15 contact each other. Thereupon, either by autodetonation of the hypersensitive chemical compounds or by subsequent shock detonation the formation is radially fractured by the explosive reaction. The resultant fracture is propagated both outward into the formation and inward towards the wellbore, thereby stimulating the production of the desired fluid by creating a more effective drainage area in the formation.

it is also within the scope of the invention to precede the treating operation herein described with a conventional hydrofracturing operation in which a hydraulic fracturing fluid is injected into the formation at a pressure at least as great as the formation breakdown pressure. in such instances, the detonation of the explosive reaction mixture would accomplish additional fracture penetration. Conventional propping agents, such as sand or aluminum, can, of course, be included with the fracturing fluid. In still another aspect of the invention, the first chemically stable liquid reactant may also be employed as a hydraulic fracturing fluid by injection at a pressure of at least the formation breakdown pressure. Conventional propping agents may also be included in this liquid reactant injected into the formation. To further enhance the fracturing effect herein provided, however, it is also within the scope of this invention to include shock-sensitive explosive pellets in place of or in addition to conventional propping agents. Such pellets, as for example aluminized shock-sensitive explosive pellets, e.g. aluminized ammonium nitrate pellets, would be detonated by the explosion of the reaction mixture formed in the formation. Such secondary detonations would enhance the propagation of the fractures outward into the formation and would tend to likewise enhance the vertical fracturing of the formation in the vicinity of the detonations.

The present invention is highly suitable for enhancing the recovery of fluids, such as oil, gas or water, from such fluidbearing formations. The explosive fracturing of the formation tends to stimulate the recovery of such fluids by creating a more effective drainage area in such formations. in addition, the resulting increase in the permeability of the formation would also tent to facilitate the recovery of oil by various secondary recovery techniques known in the art.

The present invention is also applicable with respect to the recovery of minerals, such as copper, molybdenum, uranium, lead, zinc, manganese, potash and the like, from deposit-bearing formations. The process herein described may be used to fracture such formations or to achieve rubblization thereof in such a manner as to facilitate recovery operations, such as well known leaching, solution mining, and other known techniques.

While the invention has been described above with respect to certain embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

Therefore, I claim:

1. A method of fracturing a fluid-bearing formation to stimulate the production of desired fluids therefrom comprising:

a. injecting a first chemically stable liquid reactant into the formation through a wellbore positioned therein;

b. injecting an inert spacing medium into the formation through said wellbore;

c. injecting a second chemically stable liquid reactant into the formation through said wellbore, said first and second reactants being capable of fonning explosive reaction mixtures; and

. reacting steps a) through c) of injection of reactants and spacing medium so that a series of concentric regions of reaction mixtures are formed throughout the formation in such a manner that each succeeding amount of spacing medium is decreased relative to the preceding amount of spacing medium during the treating operation,

whereby the reactants and the inert spacing medium move outward from the wellbore in circular bands, the reactants gradually approaching each other as the bands of spacing medium narrow so that the reactants can contact each other in a generally circular region of the formation around the wellbore and form the desired concentric bands of reaction mixture which, upon detonation by shock and/or the passage of time causes explosive fracturing of the formation in a radial manner with the resulting fractures propagated both outward into the formation and inward toward the wellbore, thereby stimulating the production of the desired fluid and creating a more effective drainage area in said formation.

2. The method of claim 1 in which said first and second reactions are such that the explosive reaction mixture formed in the formation autodetonates with the passage of time.

3. The method of claim 2 in which one of said reactants comprises a polynitroaliphatic reactant and the other comprises a carborane reactant.

4. The method of claim 3 in which said polynitroaliphatic reactant is tetranitromethane.

5. The method of claim 3 in which said polynitroaliphatic reactant is tetranitroglycerin.

6. The method of claim 1 in which said first and second reactions are such that the explosive reaction mixture formed in the formation rapidly becomes hypersensitive to detonation by shock and including the actuation of an auxiliary detonation device suflicient to detonate said explosive reaction mixture.

7. A method for fracturing a mineral bearing formation to facilitate the recovery of minerals therefrom comprising:

a. injecting a first chemically stable liquid reactant into the formation through a wellbore positioned therein;

b. injecting an inert spacing medium into the formation through said wellbore;

c. injecting a second chemically stable liquid reactant into the formation through said wellbore, said first and second reactants being capable of forming explosive reaction mixtures; and repeating steps (a) through (c) of injection of reactants and spacing medium so that a series of concentric regions of reaction mixtures are formed throughout the formation in such a manner that each succeeding amount of spacing medium is decreased relative to preceding amount of spacing medium during the treating operation, whereby that reactants and the inert spacing medium move outward from the wellbore in circular bands, the reactants gradually approaching each other as the bands of spacing medium narrow so that the reactants can contact each other in a generally circular region of the formation around the wellbore and form the desired concentric bands of reaction mixture, which, upon detonation by shock and/or the passage of time causes explosive fracturing of the formation in a radial manner with the resulting fractures propagated both outward in the formation and inward toward the wellbore, thereby facilitating the production of minerals from the formation by leaching, solution mining and other mineral recovery techniques.

8. The method of claim 7 in which said first and second reactions are such that the explosive reaction mixture formed in the formation autodetonates with the passage of time.

9. The method of claim 8 in which one of said reactants comprises a polynitroaliphatic reactant and the other comprises a carborane reactant.

10. The method of claim 9 in which said polynitroaliphatic reactant is tetranitromethane.

11. The method of claim 9 in which said polynitroaliphatic reactant is tetranitroglycerin.

12. The method of claim 7 in which said first and second reactants are such that the explosive reaction mixture formed in the formation rapidly becomes hypersensitive to detonation by shock and including the actuating of an auxiliary detonation device sufficient to detonate said explosive reaction mixture.

13. A method for fracturing a fluid bearing formation to stimulate the production of desired fluid therefrom comprismg:

a. injecting a first chemically stable liquid reactant into a formation through a wellbore positioned therein;

b. injecting an inert spacing medium into the formation through said wellbore;

c. injecting a second chemically stable liquid reactant into the formation through said wellbore, said first and second reactants being capable of forming explosive reaction mixtures which do not autodetonate with passage of time; and

repeating steps (a) through (c) of injection of reactants and spacing media by varying each succeeding amount of spacing medium so that the explosive reaction mixtures are formed in generally concentric regions of the formation by decreasing each succeeding amount of spacing medium relative to the preceding amount of spacing medium during the treating operation such that each cycle consists of said reactants separated by the inert spacing media, whereby the reactants and inert spacing media move outward from the wellbore in increasing circular bands, the reactants gradually approaching each other as the bands of spacing media narrow so that the reactants contact each other in a generally circular region of the formation around the wellbore to form the desired bands of reaction mixture, which, upon detonation by shock cause explosive fracturing of the formation in a radial manner with the resulting fractures propagated both outward into the formation and inward toward the wellbore, thereby stimulating the production of desired fluid by creating a more effective drainage area in said formation.

14. Method of claim 13 and including the presence of shock-sensitive propping agents in said first liquid reactant injected into said formation, the detonation of said explosive reaction mixture causing the further detonation of said explosive propping agents.

15. A method for fracturing a fluid bearing formation to stimulate the production of desired fluid therefrom comprismg:

a. injecting a first chemically stable liquid reactant into the formation through a wellbore positioned therein at an injection pressure of at least the formation breakdown pressure, whereby said injection results in the hydraulic fracturing of said formation and including the presence of shock-sensitive propping agents in said first liquid reactant injected into said formation, the detonation of said explosive reaction mixture causing the further detonation of said explosive propping agents;

b. injecting an inert spacing medium into the formation through said wellbore;

c. injecting a second chemically stable liquid reactant into the formation through said wellbore, said first and second reactants being capable of forming explosive reaction mixtures which .do not autodetonate with passage of time; and

repeating steps (a) through (c) of injection of reactants and spacing media into the formation in cycles suchthat each cycle consists of said reactants separated by the inert spacing media, whereby the reactants and inert spacing medium move outward form the wellbore in increasing circular bands, the reactants gradually approaching each other as the bands of spacing media narrow so that the reactants contact each other in a generally circular region of the formation around the wellbore to form the desired bands of reaction mixture, which, upon detonation by shock cause explosive fracturing of the formation in a radial manner with the resulting fractures propagated both outward into the formation and inward toward the wellbore, thereby stimulating the production of desired fluid by creating a more effective drainage area in said formation.

16. Method of claim 15 in which said shock-sensitive propping agents comprise aluminized ammonium nitrate pellets.

17. A method for fracturing a mineral bearing formation to facilitate recovery of minerals therefrom comprising:

a. injecting a first chemically stable liquid reactant into the formation through a wellbore positioned therein;

b. injecting an inert spacing medium into the formation through said wellbore;

c. injecting a second chemically stable liquid reactant into the formation through said wellbore, said first and second reactants being capable of forming explosive reaction mixtures which do not autodetonate with passage of time; and

d. repeating steps (a) through (c) of injection of reaction spacing medium into the formation in which each succeeding amount of spacing medium is decreased relative to the preceding amount of spacing medium during the treating and operation so that the explosive reaction mixtures are formed in generally concentric regions of the formations in cycles such that each cycle consists of said reactant separated by inert spacing medium,

whereby the reactants and their inert spacing media move out ward from the wellbore in increasing circular bands, the reac' tants gradually approaching each other as the bands of spacing media narrow so that the reactants contact each other in a generally circular region of the formation around the wellbore to form the desired bands of reaction mixture, which, upon detonation by shock cause explosive fracturing of the formation in a radial manner with the resulting fractures propagated both outward into the formation and inward toward the wellbore, therefore facilitating the production of minerals from the formation by leaching, solution mining and other mineral recovery techniques.

18. The method of claim 17 in which each succeeding amount ofspacing medium is decreased relative to the preceding amount of spacing medium during the treating and operation so that the explosive reaction mixtures are formed in generally concentric regions of the formation and including the presence of shock sensitive explosive propping agents in said liquid reactant injected into said formation.

19. The method of claim 18 and including the presence of shock sensitive explosive propping agents in said liquid reactant injected into said formation.

20. The method of claim 19 in which said shock-sensitive propping agents comprise aluminized ammonium nitrate pellets. 

2. The method of claim 1 in which said first and second reactions are such that the explosive reaction mixture formed in the formation autodetonates with the passage of time.
 3. The method of claim 2 in which one of said reactants comprises a polynitroaliphatic reactant and the other comprises a carborane reactant.
 4. The method of claim 3 in whicH said polynitroaliphatic reactant is tetranitromethane.
 5. The method of claim 3 in which said polynitroaliphatic reactant is tetranitroglycerin.
 6. The method of claim 1 in which said first and second reactions are such that the explosive reaction mixture formed in the formation rapidly becomes hypersensitive to detonation by shock and including the actuation of an auxiliary detonation device sufficient to detonate said explosive reaction mixture.
 7. A method for fracturing a mineral bearing formation to facilitate the recovery of minerals therefrom comprising: a. injecting a first chemically stable liquid reactant into the formation through a wellbore positioned therein; b. injecting an inert spacing medium into the formation through said wellbore; c. injecting a second chemically stable liquid reactant into the formation through said wellbore, said first and second reactants being capable of forming explosive reaction mixtures; and d. repeating steps (a) through (c) of injection of reactants and spacing medium so that a series of concentric regions of reaction mixtures are formed throughout the formation in such a manner that each succeeding amount of spacing medium is decreased relative to preceding amount of spacing medium during the treating operation, whereby that reactants and the inert spacing medium move outward from the wellbore in circular bands, the reactants gradually approaching each other as the bands of spacing medium narrow so that the reactants can contact each other in a generally circular region of the formation around the wellbore and form the desired concentric bands of reaction mixture, which, upon detonation by shock and/or the passage of time causes explosive fracturing of the formation in a radial manner with the resulting fractures propagated both outward in the formation and inward toward the wellbore, thereby facilitating the production of minerals from the formation by leaching, solution mining and other mineral recovery techniques.
 8. The method of claim 7 in which said first and second reactions are such that the explosive reaction mixture formed in the formation autodetonates with the passage of time.
 9. The method of claim 8 in which one of said reactants comprises a polynitroaliphatic reactant and the other comprises a carborane reactant.
 10. The method of claim 9 in which said polynitroaliphatic reactant is tetranitromethane.
 11. The method of claim 9 in which said polynitroaliphatic reactant is tetranitroglycerin.
 12. The method of claim 7 in which said first and second reactants are such that the explosive reaction mixture formed in the formation rapidly becomes hypersensitive to detonation by shock and including the actuating of an auxiliary detonation device sufficient to detonate said explosive reaction mixture.
 13. A method for fracturing a fluid bearing formation to stimulate the production of desired fluid therefrom comprising: a. injecting a first chemically stable liquid reactant into a formation through a wellbore positioned therein; b. injecting an inert spacing medium into the formation through said wellbore; c. injecting a second chemically stable liquid reactant into the formation through said wellbore, said first and second reactants being capable of forming explosive reaction mixtures which do not autodetonate with passage of time; and d. repeating steps (a) through (c) of injection of reactants and spacing media by varying each succeeding amount of spacing medium so that the explosive reaction mixtures are formed in generally concentric regions of the formation by decreasing each succeeding amount of spacing medium relative to the preceding amount of spacing medium during the treating operation such that each cycle consists of said reactants separated by the inert spacing media, whereby the reactants and inert spacing media move outward from the wellbore in increasing circular bands, the reactants gradually approaching each other as the Bands of spacing media narrow so that the reactants contact each other in a generally circular region of the formation around the wellbore to form the desired bands of reaction mixture, which, upon detonation by shock cause explosive fracturing of the formation in a radial manner with the resulting fractures propagated both outward into the formation and inward toward the wellbore, thereby stimulating the production of desired fluid by creating a more effective drainage area in said formation.
 14. Method of claim 13 and including the presence of shock-sensitive propping agents in said first liquid reactant injected into said formation, the detonation of said explosive reaction mixture causing the further detonation of said explosive propping agents.
 15. A method for fracturing a fluid bearing formation to stimulate the production of desired fluid therefrom comprising: a. injecting a first chemically stable liquid reactant into the formation through a wellbore positioned therein at an injection pressure of at least the formation breakdown pressure, whereby said injection results in the hydraulic fracturing of said formation and including the presence of shock-sensitive propping agents in said first liquid reactant injected into said formation, the detonation of said explosive reaction mixture causing the further detonation of said explosive propping agents; b. injecting an inert spacing medium into the formation through said wellbore; c. injecting a second chemically stable liquid reactant into the formation through said wellbore, said first and second reactants being capable of forming explosive reaction mixtures which do not autodetonate with passage of time; and d. repeating steps (a) through (c) of injection of reactants and spacing media into the formation in cycles such that each cycle consists of said reactants separated by the inert spacing media, whereby the reactants and inert spacing medium move outward form the wellbore in increasing circular bands, the reactants gradually approaching each other as the bands of spacing media narrow so that the reactants contact each other in a generally circular region of the formation around the wellbore to form the desired bands of reaction mixture, which, upon detonation by shock cause explosive fracturing of the formation in a radial manner with the resulting fractures propagated both outward into the formation and inward toward the wellbore, thereby stimulating the production of desired fluid by creating a more effective drainage area in said formation.
 16. Method of claim 15 in which said shock-sensitive propping agents comprise aluminized ammonium nitrate pellets.
 17. A method for fracturing a mineral bearing formation to facilitate recovery of minerals therefrom comprising: a. injecting a first chemically stable liquid reactant into the formation through a wellbore positioned therein; b. injecting an inert spacing medium into the formation through said wellbore; c. injecting a second chemically stable liquid reactant into the formation through said wellbore, said first and second reactants being capable of forming explosive reaction mixtures which do not autodetonate with passage of time; and d. repeating steps (a) through (c) of injection of reaction spacing medium into the formation in which each succeeding amount of spacing medium is decreased relative to the preceding amount of spacing medium during the treating and operation so that the explosive reaction mixtures are formed in generally concentric regions of the formations in cycles such that each cycle consists of said reactant separated by inert spacing medium, whereby the reactants and their inert spacing media move outward from the wellbore in increasing circular bands, the reactants gradually approaching each other as the bands of spacing media narrow so that the reactants contact each other in a generally circular region of the formation around the wellbore to form the desired bands of reactioN mixture, which, upon detonation by shock cause explosive fracturing of the formation in a radial manner with the resulting fractures propagated both outward into the formation and inward toward the wellbore, therefore facilitating the production of minerals from the formation by leaching, solution mining and other mineral recovery techniques.
 18. The method of claim 17 in which each succeeding amount of spacing medium is decreased relative to the preceding amount of spacing medium during the treating and operation so that the explosive reaction mixtures are formed in generally concentric regions of the formation and including the presence of shock sensitive explosive propping agents in said liquid reactant injected into said formation.
 19. The method of claim 18 and including the presence of shock sensitive explosive propping agents in said liquid reactant injected into said formation.
 20. The method of claim 19 in which said shock-sensitive propping agents comprise aluminized ammonium nitrate pellets. 